diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index b3af01da89..e192b172bf 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -381,11 +381,11 @@ static void *get_delta(struct object_entry *entry)
 	return delta_buf;
 }
 
-static unsigned long do_compress(void **pptr, unsigned long size)
+static size_t do_compress(void **pptr, size_t size)
 {
 	git_zstream stream;
 	void *in, *out;
-	unsigned long maxsize;
+	size_t maxsize;
 	struct repo_config_values *cfg = repo_config_values(the_repository);
 
 	git_deflate_init(&stream, cfg->pack_compression_level);
@@ -511,7 +511,7 @@ static inline int oe_size_greater_than(struct packing_data *pack,
 static unsigned long write_no_reuse_object(struct hashfile *f, struct object_entry *entry,
 					   unsigned long limit, int usable_delta)
 {
-	unsigned long size, datalen;
+	size_t size, datalen;
 	unsigned char header[MAX_PACK_OBJECT_HEADER],
 		      dheader[MAX_PACK_OBJECT_HEADER];
 	unsigned hdrlen;
@@ -530,11 +530,9 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
 			type = st->type;
 			size = st->size;
 		} else {
-			size_t size_st = 0;
 			buf = odb_read_object(the_repository->objects,
 					      &entry->idx.oid, &type,
-					      &size_st);
-			size = cast_size_t_to_ulong(size_st);
+					      &size);
 			if (!buf)
 				die(_("unable to read %s"),
 				    oid_to_hex(&entry->idx.oid));